This invention relates to an article of manufacture comprising polymeric materials having on its surface and coated therewith a platelet anti-aggregation compound alone, or in combination with other anti-aggregation agents and anti-thrombogenic substances, that are easily released therefrom. More particularly, the invention pertains to polymers having a platelet anti-aggregation prostaglandin incorporated into and coated onto the polymer surfaces and to polymeric materials having a prostaglandin and other anti-aggregation and anti-thrombogenic materials incorporated and coated onto the polymer surface as a means for adding these to passing, contacting biological media.
The rapid advances in polymer research with its genesis of polymeric materials has been accompanied with an accelerated use of the polymeric materials for medical engineering, for medical drug delivery devices, and medical applications for the management of health. These uses of polymeric materials for medical engineering include cardiac pacemakers, heart valve prosthesis, artificial kidneys, and heart-lung machines. The use of polymeric materials for the management of health include blood and platelet collecting systems, transfusions, the preparation of blood components for use in blood loss and the like. The use of polymeric materials as drug delivery devices include the use of these materials as solution diffusion materials for the release of a drug from a drug reservoir. Yet, in all these uses, the art has heretobefore encountered serious problems that defeated the desired aim. For example, even though there are a wide number of available polymers, such as homopolymers, copolymers, terpolymers, cross-linked polymers, thermoplastic and thermosetting polymers, and the like, the adverse effects produced by these polymeric substances has posed very serious obstacles to the successful employment of these polymers for the above mentioned purpose. These problems included the initiation of blood coagulation and the aggregation of platelets. This coagulation or thrombogenic property of polymers and the aggregation or clumping of platelets by polymers, has led the prior art, especially when it used the polymers for the manufacture of medical devices, to attempts to avoid the unfavorable disposition of these polymers. These attempts often focused on the surface electrical charge of a polymer and efforts were made to correlate the polymeric charge with the naturally occurring potential on the polymer interface but the correlations were seemingly unsuccessful. Other efforts in the art were predicated on the regulation of the flowing blood through polymeric systems to control excessive turbulence which may lead to blood coagulation and platelet aggregation and on the chemical alteration of the polymeric surface by coating the polymer with an anti-coagulant to prevent thrombic formations. It is self apparent that these latter two efforts have not met with acceptable success because of the difficulties associated with controlling the flow of liquids through conduits, the lack of a smooth internal surface, the difficulties in coating the porous lattice of a predetermined polymer and the like. Also, while the prior art has attempted to render the polymeric material non-thrombogenic, it has not seriously attempted to render the polymeric material either platelet aggregation inhibiting alone or both simultaneously aggregation inhibiting and non-thrombogenic. Other thoughts pertaining to anti-thrombogenic effects for medical devices involved the use of polyelectrolyte complex polymers having excess polycation as retardants; however, these thoughts have not offered a practical answer to the immediate problem of the present invention as presented hereinafter.
In all of the just described attempts and uses, the prior art sought to permanently bond or unite the active agent to a polymer. This too had its shortcomings, for in many instances it is both highly desirable and needed to quickly add the agent to blood or platelets. For example, in the processing of platelets starting with the collection of blood, it is now necessary to add platelet protecting agents to blood after it arrives in a collection bag. That is, during the processing, the platelets flowed unprotected through the collection apparatus. It is well known that platelets are very sensitive and rendered non-viable during such unprotected processing. Additionally, the prior art never conceived or attempted to produce any articles of manufacture that easily released an active agent to a platelet media. That is, the prior art never made an article of manufacture where an active platelet protecting agent is imbibed and surface coated onto a polymer for easy release of the agent on mere contact to the flow of a passing liquid. It will be appreciated by those versed in the art to which the invention pertains that a critical need exists for an article that easily releases an active agent to protect platelets for retaining their properties for use in health and disease.